Tire pressure measuring device



ug. 9, 1938. l w. H. HENDEL ET A1. 2,126,327

TIRE PRESSURE MEASURING DEVICE Filed May 2l, 1936 william Hmmm and vAlexander Gr. Hendelv Gxtommg Patented Aug. 9, 1938 UNlTE STATES TIREPRESSURE MEASURING DEVICE William H. Hendel and Alexander G. Hendel,Minneapolis, Minn.

Application May 21, 1936, Serial No. 80,972

12 Claims.

Our invention relates to devices for measuring the pressure of pneumatictires and has for its object to provide a fluid operated device capableof indicating the pressure in a tire without removal of the valve capthereof or the release of any of the air from the tire.

An object of the invention resides in providing a iiuid operated device,over which the tire on a vehicle may be run and by means of which thepressure in the tire may be indicated through the action of the unitpressure of the tire on such device.

Another object of the invention resides in providing a device of thecharacter referred to which will not require accurate spotting of thetire.

A still further object of the invention resides in providing a devicecapable of indicating tire pressure when the tire is partly supported bythe device.

An object of the invention resides in providing a hollowcontractiblebody having a iiuid therein, said body being adapted to be contracted byengagement of a tire therewith and in further providing a pressureresponsive device connected with said hollow body subject to thepressure of the fluid for indicating the pressure within the tireapplied to the body.

Another object of the invention resides in providing a plate having acavity therein and in disposing within said cavity a fluid tight sack offlexible material adapted to be compressed by a tire resting upon theplate.

A still further object of the invention resides in constructing saiddevice in the form of a mat or tread, over which the vehicle tire may berun.

Another object of the invention resides in providing a device which willbe small and compact in size.

An object of the invention resides in constructing the ccntractible bodywith two spaced walls and in providing cords extending between saidWalls for restraining said Walls from movement away from one another.

Another object of the invention resides in profili viding an elongatedcontractible member of a length greater than the width of the supportingarea of the tire and of a width less than the length of the supportingarea of the tire for engagement with the tire. 50 Other objects of theinvention reside in the novel combination and arrangement of parts andin the details of construction hereinafter illustrated and/ ordescribed.

In the drawing l Fig. 1 is a perspective View of a pressure measuringdevice illustrating an embodiment of our invention.

Fig. 2 is a longitudinal sectional view of the structure shown in Fig.1, illustrating a tire resting upon the same. 5

Fig. 3 is a cross sectional View taken on line 3-3 of Fig. 2 and drawnto a slightly larger scale.

Fig. 4 is a view similar to Fig. l of a modification of the invention.

Fig. 5 is a fragmentary longitudinal sectionallo view of one portion ofthe mat shown in Fig. 4, drawn to an enlarged scale.

This application for patent is a continuation in part of our copendingapplication for patent, Serial No. 510,184, filed January 21, 1931 and i15 which has matured into a Patent No. 2,051,042.

In the measuring of the pressure of pneumatic tires, considerabledifficulty and inconvenience is encountered in the ordinary method inremoving the valve caps and applying to the valve stems the #20 ordinarypressure gauge now available for such purpose. Furthermore, measuring oftire pressure by such methods requires: more or less time and is arather dirty task. The instant invention overcomes these disadvantagesby providing a device over which the tire of a vehicle may be run, andwhich will directly and without effort to the observer, indicate thepressure of the tire resting upon the same. The present inventioncontemplates the use of one or more measuring devices to be utilized onone or more of the tires, so that the pressures of the various tires besimultaneously indicated. The invention further contemplates: the use ofthe measuring device as a portable structure capable of being brought tothe f vehicle and placed on any floor or surface and the vehicle runupon the same and also contemplates the permanent mounting of thedevices in conjunction with run-ways leading up to the same and with thevarious pressure gauges all situated 4@ in close proximity to oneanother to permit of readily ascertaining the pressures in the varioustires.

For the purpose of illustrating the application of the invention, aportion of a vehicle tire B has been shown, which comprises the usualcasing l2,

mounted upon a wheel of the vehicle which has been partly shown at de.The tire illustrated is assumed to be inflated and the contactingsurface thereof when supporting the vehicle proper is 5() designated bythe numeral I3 in Figs. 2 and 3.

In Figs. 1 to 3 inclusive, we have shown one form of the invention. Thisdevice comprises a tread or mat which we have indicated in its entiretyat 30 and which is planiform and of a 55 relatively thin thickness. Thismat may have an area either less than or greater than the supportingsurface i3 of the tire Whose pressure is to be measured. The mat 3d isprovided with a plate-like member 3i constructed of Wood, iiber, metalor some other similar substance capable of supporting the major portionof the weight of the tire Without appreciable deformation. This plate isbeveled at its ends to divide ramps designated by the referencecharacters 32 and 33 and is formed at the central portion thereof with acircular opening 34, extending completely through the same. Within thisopening is placed a sack 35 of rubber or some other suitable huid tightflexible material, which is connected through an armored hose 3G with agauge 37 of the Bourdon type or its equivalent. The hose 36 passesthrough an opening 323 in the plate 3i, which communicates With theopening Sli. The sack 35 is preferably cylindrical to substantiallyoccupy the entire space formed by the opening 34 in the plate 3 l, whenin its normal position. The entire mat or tread 3@ may be covered with acovering of canvas 39 to protect the same and particularly the sack 35.

For actuating the gauge 31, the chamber within the sack 35, hose 3S andthe actuating member of gauge 37 are filled with any suitable huid.Liquids such as glycerine, alcohol, Water, certain types of oil,castor-oil, various types of mineral and vegetable oils, mercury andmixtures of such liquids may be used. Where a gas is employed, air ispreferable, though any other inert gas may be utilized, which Will notreact With the material with which the mat is formed. Such gas may beunder pressure if desired, depending upon the construction of 'thedevice and the type of pressure responsive mechanism employed.

For the purpose of lling the device With the fluid, any suitable meansand method may be used, such as is now Well known in the art. A tubeconnected to the sack 35 may be provided, which is sealed after thedevice is lled. Suitable hose connections may be provided at each end ofthe hose, which may be disconnected when it is desired to fill thedevice. After the device has been lled, the connections may again beattached to bring the gauge into communication with the contractiblechamber.

In the operation of`our invention, the tire which is indicated at B isrun over the tread 353 until the contacting surface i3 thereof coversthe central portion of the same containing the sack The portion Si beingnon-yielding and substantially incompressible, supports the majorportion of the weight on the tire, While the sack being relativelycontractible, receives a certain deformation, depending upon thepressure of the air in the tire proper. This causes a reading of thegauge 3?, which may be calibrated to directly indicate the air pressureWithin the tire. We have found that the unit air pressure in the tire issubstantially proportional to the gauge reading, indicating that theunit pressure in the tire is transmitted through the upper portion ofsack 35, and through the liquid therein to the gauge proper.

Although we have shown and described a single mat or tread for use withone of the tires of the vehicle at a time, it can readily becomprehended that four such mats may be employed and permanently ortemporarily mounted so that the Vehicle may be driven with all thewheels thereon resting upon the mats. It is also to be understood thatthe gauges from the various mats or treads may be assembled collectivelyand, if desired, in a single case, so .t pressure in all of the tiresmay be quickly ascertained. Although We have shown the structure for'forming the contractible chamber as constructed of rubber or some otherresilient material, it can readily be comprehended that the same may beconstructed in various different forms.

In Figs. 4 and 5 We have shown another form of the invention in which anelongated sack fli is used in place of the cylinder sack In this devicea plate-like member l2 is used in place of the member 3l which isidentical therewith except that the same is constructed with anelongated opening or cavity 53 therein instead of the cylindricalopening 3d. This plate-like member has sloping ends or ramps lf3 and l5similar to the ends 82 and 33.

The elongated sack lll is constructed of rubber or some other suitableflexible material and is provided with spaced upper and lower Walls #l5and il which are connected together by side Walls iii and i9 and endWalls, not shown. Imbedded in the side Walls d8 and lil are reinforcingcords '5i and connecting the Walls i5 and il together are cords 52 whichare closely positioned and which limit movement of the Walls away fromone another, but permit movement toward one another. These cords arestitched through the Walls and lil, and the ends of the reaches thereof'are securely imbedded in said Walls to resist the stress to which thewalls are subjected and to provide a fluid tight construction.

The sack el is connected by means of an armored hose 53 with a pressuregauge 5d of the Bourdon or equivalent type. The entire device includingthe sack di, hose 53 and the actuating element of gauge Sli arecompletely filled with some suitable fluid as previously described. Acovering 39 covers the members lli and 42.

The operation of the form of the invention disclosed in Figs. 4 and 5 issimilar to that disclosed in Figs. l, 2 and 3. The tire is run on themat 352 until the same rests partly on the mat and partly on the sacklll. The sack All is longer than the Width of the contacting surface ofthe tire so that the entire surface of the sack is not covered. Thecontacted part of the sack becomes depressed and the cords 52 yield topermit of compression While the part not contacted remains in normalposition, movement of the Walls El and il thereof away from each otherbeing restrained by said cords. We have found that the unit pressure inthe tire causes a corresponding pressure indication on the gauge whichmay be calibrated to read directly the unit pressure in the tire.

The invention is highly advantageous in that an extremely simple andeffective device is produced whereby the pressures in the tires ofvehicles may be quickly and positively determined without removing thecaps and applying a pressure gauge to the tire valves. The device may beconstructed Without jointed metal parts if desired, so as to eliminatethe disadvantages following mechanical devices embodying suchconstruction. The device is extremely positive in action andsufficiently accurate for the desired purpose. The gauges can becalibrated to read directly in pounds per square inch of pressure,indicating the exact air pressure Within the tire. The device can beconstructed from readily available materials and at an extremelyeconomical price, so that the same may be universally sold and adopted.The device may be made so that Y .be run or the same may be portable andmoved about as desired.

Changes in the specific form of our invention Vas herein ydisclosed maybe made within the scope of what is claimed, without departing from thespirit of our invention. Y

Having described our invention, what we claim as new and desire toprotect by Letters Patent l. A pneumatic tire pressure measuring devicecomprising a substantially incompressible support having an uppersurface for carrying a portion of the load on a pneumatic tire, saidsupport having a cavity therein. extending through said surface, acontractible sack occupying the space provided by said cavity and havinga fluid therein, and carrying another portion of the load on the tire,and pressure responsive means connected with said sack and responsive tothe pressure of said fluid for indicating the pressure within the tire.

2. A pneumatic tire pressure measuring device comprising a substantiallyincompressible support having an upper surface for carrying a portion ofthe load on a pneumatic tire, said support having a cylindrical cavitytherein extending through said surface, a contractible cylindrical sackoccupying the space provided by said cavity andhaving a iiuid thereinand carrying another portion of the load on the tire, and pressureresponsive means connected with said sack and responsive to the pressureof said fluid for indicating the pressure in the tire.

3. A pneumatic tire pressure measuring device comprising a substantiallyincompressible support having an upper surface for carrying a portion ofthe load on a pneumatic tire, said support having an elongated cavityextending through said surface, an elongated contractible sack occupyingthe space provided by said cavity and having a uid therein, said sacksupporting a portion of the load on the tire and pressure responsivemeans connected to said sack and subject to the pressure of the fluidtherein for indicating the pressure in the tire.

4. A pneumatic tire pressure measuring device comprising a substantiallyincompressible support having an upper surface and forming a run- Wayfor supporting a portion of the load on a pneumatic tire, saidl supporthaving a transverse groove therein extending through said surface, anelongated hollow contractible member occupying the space provided bysaid groove and having a fluid therein, said contractible membersupporting a portion of the load on the tire, and pressure responsivemeans connected to said contractible member and subject to the pressureof the fluid therein for indicating the pressure in the tire.

5. A pneumatic tire pressure measuring device comprising a substantiallyincompressible support having an upper surface and forming a runway forsupporting a portion of the load on a pneumatic tire, said supporthaving a transverse groove therein extending through said surface, anelongated hollow contractible member occupying the space provided bysaid groove and having a fluid therein, said contractible membersupporting a portion of the load on the tire, and being of a lengthgreater than the width of the supporting surface of the tire and of awidth less than the length of such surface, means for restrainingexpansion of said contractible member, and pressure responsive meansconnected to said contractible member and subject to the pressure of theuid therein for indicating the pressure in the tire.

6. A pneumatic tire pressure measuring device comprising a substantiallyincompressible support having an upper surface and forming a runway forsupporting a portion of the load on a pneumatic tire, said supporthaving a transverse groove therein extending through said surface, anelongated hollow contractible member occupying the space provided bysaid groove and having a fluid therein, said contractible membersupporting a portion of the load on the tire, and being of a lengthgreater than the width of the supporting surface of the tire and of awidth less than the length of such surface, said contractible memberhaving two spaced walls, tethering members extending between said wallsand restraining spreading thereof, and pressure responsive meansconnected to said contractible member and subject to the pressure of theuid therein for indicating the pressure in the tire.

7. A pneumatic tire pressure measuring device comprising a supporthaving an upper surface on which a portion of a tire rests, said supporthav- .ing a cavity therein extending through said surface, a receptacleoccupying the space provided by said cavity and being provided with apressure transmitting member having a surface forming substantially acontinuation of the surface of said support and on which another portionof the tire rests, and pressure responsive means connected with saidreceptacle and subject to the pressure of said fiuid for indicating thepressure in the tire.

8. A pneumatic tire pressure measuring device comprising a supporthaving an upper surface on which a portion of a tire rests, said supporthaving a cylindrical cavity therein extending through said surface, acylindrical receptacle occupying the space provided by said cavity andbeing provided at one end with a pressure transmitting member having asurface forming substantially a continuation of the surface of saidsupport and on which another portion of the tire rests, and pressureresponsive means connected with said receptacle and subject to thepressure of said fluid for indicating the pressure in the tire.

9. A pneumatic tire pressure measuring device comprising a supporthaving a supporting surface on which a portion of a tire rests, areceptacle having a fluid therein and having a pressure transmittingmember provided with a supporting surface lying adjacent to andsubstantially in continuation of the supporting surface of said supporton which another portion of the tire rests, and pressure responsivemeans connected with said receptacle and subject to the pressure of saidfluid for indicating the pressure in the tire.

l0. A pneumatic tire pressure measuring device comprising a supporthaving an upper surface on which a portion of a tire rests, a receptaclehaving a iuid therein, pressure transmitting means provided with asupporting surface lying adjacent to and substantially in continuationof the supporting surface of said support on which another portion ofthe tire rests, said pressure transmitting means being arranged totransmit pressure to said Huid, and pressure responsive means connectedwith said receptacle and subifio ject to the pressure of said fluid forindicating the pressure in the tire.

11. A pneumatic tire pressure measuring device comprising a supporthaving an upper surface on which a portion of a tire rests, a receptaclehaving a uid therein and having a pressure transmitting member providedwith a surface forming a substantially unbroken continuation of theupper surface of said support and disposed at substantially the sameelevation as said surface and on which another portion of the tirerests, and pressure responsive means connected with said receptacle andsubject to the pressure of said fluid for indicating the pressure in thetire.

12. A pneumatic tire pressure measuring device comprising a supporthaving an upper surface on which a portion of a tire rests, a receptaclehaving a fluid therein, a covering for said receptacle over-lying thesame and constituting a pressure transmitting member provided with asurface lying adjacent to and substantially in continuation of the uppersurface of said support and on which another portion of the tire restsand pressure responsive means connected with said receptacle and subjectto the pressure of said fluid for indicating the pressure in the tire.

WILLIAM H. HENDEL. ALEXANDER G. HENDEL.

